11685991 has 2 divisors, whose sum is σ = 11685992. Its totient is φ = 11685990.

The previous prime is 11685983. The next prime is 11686009. The reversal of 11685991 is 19958611.

It is a weak prime.

It is an emirp because it is prime and its reverse (19958611) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11685991 - 2³ = 11685983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11685911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5842995 + 5842996.

It is an arithmetic number, because the mean of its divisors is an integer number (5842996).

Almost surely, 2^11685991 is an apocalyptic number.

11685991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11685991 is an equidigital number, since it uses as much as digits as its factorization.

11685991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 40.

The square root of 11685991 is about 3418.4778776526. The cubic root of 11685991 is about 226.9282248318.

The spelling of 11685991 in words is "eleven million, six hundred eighty-five thousand, nine hundred ninety-one".